Steve Carell plays John du Pont in Bennett Miller’s wrestling drama “Foxcatcher,” which premiered today at the Cannes Film Festival, and the moment the actor appears on screen, it takes a few moments to recognize him.

That’s because Carell has completely transformed into the millionaire Du Pont: high nose bridge, absent eyes and general aloofness interrupted by rare, startling moments of humanity. Du Pont vies with his mother, played by Vanessa Redgrave, for bragging rights in athletics – to her disdain, his obsession is the sport of wrestling.

“Foxcatcher,” directed by Bennett Miller (“Moneyball,” “Capote”) examines the period when Du Pont invited and hosted the Schultz brothers, both Olympic gold medal wrestlers, to stay at his estate near Philadelphia and train a world-class wrestling team called “Team Foxcatcher.” Mark Ruffalo plays older brother David, and Channing Tatum is the impressionable younger brother, Mark. Miller follows the time they shared with Du Pont unflinchingly to its tragic end.

“Foxcatcher” is primarily told through Mark’s point-of-view, and much of the film observes his frail relationship with du Pont. Where Tatum’s Mark is eager to please and ambitious, Carell’s du Pont is mercurial and demanding — he wakes Mark in the middle of the night just to spar together on the wrestling mat, and he encourages Mark to experiment with drugs even while he’s training for competitions.

“Obviously there’s a history of the Du Pont legacy so I did as much research as I could,” Carell said at a press conference for the film Monday. He watched video footage and documentaries that du Pont had commissioned about his own life.

“It’s difficult to say exactly what motivated him and what demons he had lurking inside of him, but I think … we were able to decide internally what this character’s motivation was and what his demons might have been,” Carell said.

“You can do all sorts of research and listen to someone’s voice and watch them but I think ultimately you forget all about that when you start to shoot,” Carell added. “If you’ve rehearsed enough, it’s inside of you when you’re doing it.”

Miller recalled the first article he read about Du Pont and the Schultz brothers.“These guys were down there with this guy who didn’t know anything about wrestling, but he was the head coach of a team of guys who were among the best in the world, certainly the best in the country,” he said. “First question, what’s the transaction and how honest are they with each other about it?”

Miller said after he met Carell and discussed the part, he knew he had found his Du Pont. “[This] obviously doesn’t resemble anything he has done before,” Miller said. “I asked Steve if he could imagine what life would really be like if he did not have the relief of a sense of humor. Not just being funny but to see humor in things.”

Carell went “to a dark place,” Miller said, adding that he thinks all comedians are dark. “I just thought, he could do it.”

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